In the related art, for measuring a pulse of a human, a method in which a measurer (such as a nurse) manually checks a pulsation by contacting a wrist of a subject with a finger, a method in which a dedicated measuring equipment is attached to a wrist, a finger, or the like of a subject so as to automatically detect the pulsation, and the like are known. On the other hand, in these measuring method, free behavior of a subject is temporarily restricted or there is need to attach measuring equipment on a subject. Therefore, a technology for estimating (detecting) a pulse without contact with a subject (human body) is developed.
For example, in a technology of detecting a heart rate (in general, equivalent to a pulse rate) without contact with a human body, a heart rate detection device, that automatically detects the heart rate, is known in which spectrum density of a time series signal is extracted from an image data obtained by imaging a subject, and a peak frequency caused by a heartbeat signal is specified from the spectrum density (refer to PTL 1).
In addition, in a technology of calculating the heart rate from an acquired pulse wave, for example, a photometric device for a living body is known in which a light detector detects a light that has emitted from a light irradiator and transmitted through an inside of a subject, and the heart rate is calculated from two continuous peaks of the pulse wave shown in a measurement signal obtained by the light detector (refer to PTL 2).